In ancient mythology, Nike was the Greek goddess of victory. Today, Nike, the global athletic shoe and apparel company, is extending its victory to social media. Among all U.S. companies, Nike was the most responsive to customers who contacted it via social media sites such as Facebook and Twitter, according to Socialbakers, a provider of social media measurement and analytics.

Nike dominated the top 10 U.S. list and was number four on the worldwide list. Nike's main customer support handle, @NikeSupport, has a 79.5 percent response rate. Response time was 140 minutes on average.

Other companies rounding out the U.S. list included Chase, Nokia, and JetBlue. Chase posted a 67.3 percent response rate and replied to posts in 200 minutes. Nokia had an 86.1 percent response rate, and replies took 207 minutes on average. JetBlue, through its @JetBlueAirways handle, logged a response time of 13 minutes on average, and the company responds to 79.1 percent of all tweets.

On the world stage, big-box retailer Tesco was first, with a 65.9 percent response rate, replying to posts in just 81 minutes. Other world leaders included Vodafone, O2, Safaricom, Telstra, Royal Dutch Airlines, and American Airlines.

Not surprisingly, both the U.S. and worldwide lists were dominated by telecom companies and airlines, two industries where online customer service has become critically important to their success. In these industries, companies "can lose customers very quickly, so they need to use social media for a competitive edge," explains Jan Rezab, CEO of Socialbakers. "They need to build trust with their customers, and one of the keys to that is responding when they have a problem."

JetBlue, American Airlines, and WestJet were the top U.S. airlines on the list. American, which also finished ninth on the worldwide list, was singled out for having among the lowest response times. The company responds to 75.2 percent of all posts and answers questions in just 12 minutes on average; only Halo BCA, a small Indonesian banking firm, was found to have quicker response times, at three minutes, but it, quite obviously, has far less traffic on its Twitter page. WestJet responds to 73.7 percent of all posts.

To make the "socially devoted" list, companies need at least a 65 percent response rate to all social media posts directed to them specifically.

For many, that could mean reacting outside normal business hours, Rezab says."We can't expect every company to be on 24/7, but someone should be able to be alerted to issues before normal business hours," he says.

According to Socialbakers research, roughly 60 percent of all questions posted to companies' Twitter handles are logged between 5 p.m. and 9 a.m.

"People are going to social media because they expect to get a response," Rezab tells CRM. "They started demanding social customer service, and companies are finally starting to respond."

Though there are no hard and fast rules for when to respond, Rezab says companies should take a cue from social norms around text messaging. "If you send a text message to a friend, how soon do you expect a response?" he asks. "It should be the same for brands on social media."

Companies on the "socially devoted" list have also demonstrated a commitment to doing social customer service well, incorporating social media into the company culture, and putting in place the right organizational structure to handle social media interactions, according to Rezab.

"You should have one central account for customers to reach you, where you can address their complaints," he adds. "Some companies can get away with having two people [to handle social media], and some could need thirty or more, depending on the company and what it wants to do. But you should make it an in-house effort and find the right partners to help you."

The benefits, he adds, go beyond customer service. Companies that are more responsive also see lifts in cross-sell and upsell opportunities and customer retention, Rezab says.

"Social media is now an official customer service channel," he observes. "It's extremely important to be on social, to provide a presence and a response."